Quest to Validate and Define Performance for the High Volume Metallic Stator PCP at 250°C

Abstract

ConocoPhillips has been on a quest to find a high volume artificial lift system that will operate reliably in a 250°C (482oF) downhole environment, which exists in certain SAGD applications. This presented two problems:there were no commercially available technologies for such a high temperature; andthere were no facilities capable of testing these systems. This paper describes the complexity of building and operating a high temperature flow loop rated for 250°C, and the lessons learned while upgrading an existing flow loop, from the initial design through the final commissioning phases. The paper also describes the issues encountered with the first artificial lift system tested at 250°C, which was a metallic stator progressing cavity pump system, rated for 1100 m3/d (6919 bpd) at 500 rpm. In the end, the test program not only served to validate and define the pump's performance, but also provided valuable lessons on the completion configuration and operational procedures. Introduction The ConocoPhillips technology group was tasked to find, select, and further develop artificial lift technology with the capability of handling fluid rates up to 1000 m3/d at 250°C (6290 bpd at 482oF) downhole conditions. The goal was not to just find and validate a single system, but to qualify several lift systems, in order to provide the production engineers with a "toolbox" of solutions. This challenge was divided and approached as two different projects:find, select and further develop potential lift systems with the needed volumetric capability; andvalidate these systems through high temperature testing. The latter was considered to be the bigger challenge of the two. ConocoPhillips did not operate any fields with downhole temperatures close to 250°C, so validation via field trial was not possible. A more controlled test facility (whether a well or flow loop) was also preferred, so that a comprehensive suite of performance curves could be collected to define the full operating envelope for each lift candidate. A test facility which was not associated with a specific pump vendor was also preferred, to avoid the legal and confidentiality issues with testing third party equipment. ConocoPhillips decided that an existing high temperature flow loop located at C-FER Technologies Ltd, in Edmonton, Alberta, Canada was the best option for the artificial lift validation testing. The loop had been built as part of a Joint Industry Project (JIP)1 in 2004, but needed to be upgraded to allow for testing at 250°C. This was a costly endeavor, and ConocoPhillips and C-FER contacted other Canadian SAGD operators to see if the upgrade could be completed as a JIP, thus sharing the capital cost among several interested parties. However, no other operators were interested in upgrading the loop at the time, so ConocoPhillips proceeded to fund the project entirely.

Study on Speed and Clearance Optimization of All-Metal Progressing Cavity Pumps: Experiment and Simulation

“… 5 In the field of oil mining, workers often adopt the mining method of heating the formation to reduce the viscosity of crude oil and artificially create a high-temperature environment to improve the recovery factor. 6 − 10 Therefore, the application of traditional rubber screw pumps is limited, and all-metal screw pumps came into being. 11 − 14 The stator and rotor of the all-metal screw pump are composed of metal.…”

“…The manufacturing process of such a rubber screw pump is simple, but in a high-temperature environment, the rubber is easy to age . In the field of oil mining, workers often adopt the mining method of heating the formation to reduce the viscosity of crude oil and artificially create a high-temperature environment to improve the recovery factor. − Therefore, the application of traditional rubber screw pumps is limited, and all-metal screw pumps came into being. − The stator and rotor of the all-metal screw pump are composed of metal. In order to ensure successful assembly, there must be a gap between the stator and the rotor, but this will cause leakage. − If the gap is too large or too small, it will seriously affect the pump efficiency; so the optimization of the gap size affects the design and use of the entire pump. − …”

Analytical Model for the Flow in Progressing Cavity Pump with the Metallic Stator and Rotor in Clearance Fit

“…However, due to the characteristics of the elastomeric stator and the interference fit, the conventional PCP has some shortcomings in temperature resistance (<160 ∘ C) and abrasion resistance [7], which limits its application in oilfield, especially in thermal production wells. Therefore, the PCP with the metallic stator and rotor, also known as all metal PCP, becomes recognized as an alternative artificial lift method for both the cold and thermal production [8,9]. It is applicable to a larger range of temperature almost up to 350 ∘ C, due to the high temperature tolerance of the metallic stator.…”